Kākāpō in good genetic health despite inbreeding
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Posted September 10, 2021
Media Release: Science Media Centre NZ
Analysis of almost 50 kākāpō genomes has found the current population on Rakiura/Stewart Island is more in-bred – but shows fewer harmful mutations – than a now-extinct mainland population.
One explanation is that Rakiura kākāpō may have “purged” more harmful mutations than their mainland relatives, from whom they separated around 10,000 years ago. The international research team, which includes New Zealanders, says their analysis shows small populations can survive even when isolated for hundreds of generations.
The SMC asked experts to comment on the research.
Dr Ang McGaughran, Senior Lecturer, Te Aka Mātuatua – School of Science, University of Waikato, comments:
“I got really excited when I saw just the title of this paper. And, upon reading it, I wasn’t disappointed! It’s got a little bit of everything: a focus on a precious taonga species (the kākāpō), the use of genome sequencing to understand the current status of this endangered bird, ‘museomics’ – the use of historical specimens – to ‘go back in time’ and tell us about the kākāpō’s evolutionary history, and the finding of some cool results that have strong conservation implications and challenge our way of thinking in the evolutionary space.
“We expect small, inbred populations to be at high risk of extinction, but these authors found that actually, these small populations have less mutations of negative effect than anticipated. This challenges our expectations and means that small populations can sometimes be better at coping with the associated genetic effects than we’d thought.
“Another key finding is that kākāpō on Stewart Island likely became isolated there before it separated from the South Island – we had previously thought that humans introduced the birds to Stewart Island in the last ~500 years. But this tells us that instead, kākāpō have a longer independent history in the South of New Zealand than expected, adding another line of evidence to the authors’ hypothesis that small populations can survive well, even in isolation and over long time periods.
“Just as the COVID pandemic has outlined the strength of genome sequencing for telling us about relationships among viral strains, this paper emphasises the importance of genomic tools in telling us about how treasured birds of Aotearoa are related to each other. It also provides us with vital information about how to proceed with future conservation efforts to give the kākāpō the best chance of survival into the future. I hope that this paper paves the way for future genomic work on endangered species, both in New Zealand and beyond.”
Photo: Kakapo - Department of Conservation